JSON to JSON Lines Converter
This converter turns a JSON array into JSON Lines, the format where each line is one complete JSON value. That format is what log pipelines, BigQuery, streaming APIs and most large-scale data tools expect, for one concrete reason: a file can be read and processed one line at a time without loading the whole thing into memory, and a new record can be appended without rewriting anything. A wrapper object holding a single array is unwrapped automatically, so an API response shaped like the usual data envelope converts the records rather than the envelope around them.
How it works
Turns an array into JSON Lines, where each line is one complete JSON value. That format is what log pipelines, BigQuery, streaming APIs and most data tools expect, because a file can be processed one line at a time without loading it all into memory.
A wrapper object holding a single array is unwrapped automatically, so an API response shaped like {"data": [...]} converts the records rather than the wrapper.
Everything runs in your browser — nothing you paste is sent to a server.
Why the format exists
A JSON array has to be read in full before it can be parsed, because the parser cannot know it has a complete document until it reaches the closing bracket. For a 40GB export that is not a workable requirement.
JSON Lines removes the enclosing array. Each line stands alone, so:
- A file can be streamed and processed line by line at constant memory.
- A record can be appended by writing one more line — no rewriting.
- A corrupt line loses one record rather than the whole file.
- Standard line-based tools such as grep, head and split work on it directly.
Formatting matters
Each record must be on exactly one line, which means it cannot be pretty-printed. That is why the output here is compact — a record containing a newline would break the format entirely.
Frequently asked questions
What is JSON Lines?
A format where each line of a file is one complete JSON value. Also called NDJSON or line-delimited JSON. There is no enclosing array and no commas between records.
Why use it instead of an array?
A file can be processed one line at a time without loading it all into memory, and a record can be appended by writing one more line. Neither is possible with a single enclosing array.
What if my JSON is wrapped in an object?
A wrapper holding exactly one array is unwrapped automatically, so a response shaped like {"data": [...]} converts the records inside it.
Which tools expect this format?
BigQuery, Elasticsearch bulk endpoints, most log shippers, and the streaming responses of many APIs.
What file extension should I use?
.jsonl is the most common, with .ndjson also widely recognised. Both mean the same thing.
Is my data uploaded?
No. The conversion happens entirely in your browser.
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